Safe and efficient aircraft operation requires accurate temperature measurements. Total air temperature (TAT) probes, typically positioned outside the fuselage or at the engine inlet, measure the maximum air temperature attained by converting the kinetic energy of the surrounding airstream to thermal energy. TAT probes stagnate the surrounding free stream airflow to measure the static air temperature and the resulting adiabatic rise in temperature. Aircraft operators use this measurement and values derived therefrom for, among other things, true air speed calculations and fuel burn monitoring.
Icing conditions can be problematic for the accuracy of TAT measurements. During in flight icing conditions, solid particles, ice crystals, ice particles, and/or water droplets can accumulate on the sensing element within the probe, resulting in erroneous measurements. Conventional TAT probe designs use streamlined airflow passages and an inertial separation bump to prevent these particles from accumulating on the sensing element; however, these airflow geometries create impact surfaces for ingested particles. Impact surfaces cause deflection, fracturing, and small particle generation that increase the likelihood of accumulation on the sensing element and, as a result, measurement error. Additionally, more accurate TAT measurements may be necessary to meet rising aircraft cost and performance demands.